The present invention relates to an apparatus and method for eliminating dislodged thrombus in a blood vessel.
Removal of thrombus from human vasculature may be accomplished via a traditional open surgical procedures, or via endovascular procedures. While open surgical procedures remain the standard for many cases, endovascular procedures are typically less invasive and often decrease the time between diagnosis and treatment. This is especially critical, for example, in lysis of a cerebrovascular clot for treatment of an acute stroke.
Current endovascular techniques for removing thrombus include mechanical and chemical approaches. Known mechanical approaches include perturbation of the thrombus via physical scraping, the application of a pressure gradient, and electromechanical stimulation. Known chemical approaches include intravenous (or systemic) delivery of a thrombolytic agent and selective delivery of a thrombolytic agent through an infusion catheter. It can be advantageous with both mechanical and chemical approaches to use a filter device to trap thrombus dislodged during the endovascular procedure and thereby prevent the dislodged thrombus from traveling downstream in the vasculature.
One of the challenges faced by surgeons using endovascular techniques to remove thrombus is the wide variation in size (axial length) of the thrombotic material. Thrombotic material in vasculature frequently ranges from 5 cm to 30 cm in axial length, requiring the surgeon to select an infusion catheter having the proper infusion length. Sometimes this selection process may occur prior to surgery, but other times the selection of the infusion catheter occurs during surgery, which requires an assortment of infusion catheters having various infusion lengths to be brought into surgery. Hence, a need exists for an infusion catheter in which the infusion length can be varied according to the size of the thrombus.
Another challenge faced by surgeons using endovascular techniques to remove thrombus arises when dislodged thrombus is trapped in a filter. The filter is typically inserted into the vasculature through a relatively small catheter. Often, the dislodged thrombus includes relatively large sections which make it difficult to retract a filter filled with such large sections of thrombus. Hence, a need exists for a thrombolysis apparatus which sufficiently reduces or, ideally, completely dissolves the thrombus trapped by the filter so that the filter can be easily retracted and removed.
The present invention is an apparatus for eliminating dislodged thrombus in a blood vessel. The apparatus comprises a catheter having a plurality of infusion ports and a filter attached to the catheter for trapping dislodged thrombus carried by blood flow in a blood vessel. The plurality of infusion ports are disposed within the filter and are operable to deliver a thrombolytic fluid to dissolve the dislodged thrombus trapped in the filter.
In accordance with another aspect, the present invention is an apparatus for eliminating dislodged thrombus in a blood vessel. The apparatus comprises relatively movable first and second tubular members. The first tubular member is partially disposed coaxially within the second tubular member. The first tubular member includes a plurality of infusion ports for delivering a thrombolytic fluid. A filter member is attached to the first and second tubular members. The filter member is radially expandable by relative movement between the first and second tubular members to stretch across the blood vessel and trap dislodged thrombus carried by blood flowing through the blood vessel. The plurality of infusion ports are located within the filter member and oriented to direct the thrombolytic fluid against the dislodged thrombus trapped in the filter member and thereby dissolve the dislodged thrombus.
According to another aspect of the present invention, a method for eliminating thrombus attached to a wall of a blood vessel is provided. According to the inventive method, a radially expandable filter assembly is inserted into the blood vessel downstream from the thrombus. The filter assembly includes a filter basket having a plurality of infusion ports disposed within the filter basket. The filter assembly is radially expanded to extend across the blood vessel. The thrombus is dislodged from the wall of the blood vessel. The dislodged thrombus is then trapped in the filter basket A thrombolytic agent in infused through the filter assembly and directed, through the plurality of infusion ports, into the filter basket to dissolve the thrombus trapped in the filter basket.